Fiber optic circuits are finding increasing uses today in a variety of applications for carrying signals which have heretofore been transmitted in electrical form. For example, railway cars, particularly for passenger applications, use a variety of control circuits which must be mated to the control circuits in adjacent cars. The electrical circuits control a variety of applications such as heating and cooling of the cars, the status of safety features such as temperature sensors and sensors to detect the performance of safety related items such as brakes, and for communications such as for intercoms and signaling devices to permit a conductor to provide information to passengers and to the operator of the train. Heretofore, connections of electrical signals for the foregoing applications between adjacent cars were made by connecting multicontact electrical connectors to carry signals of the foregoing type between adjacent cars. When it was desired to remove or add a car from a train to lengthen or shorten the train (depending upon the passenger load factor) it was necessary for a railroad employee to manually connect or disconnect the electrical connectors between adjacent cars to effect a connection or disconnection of the control signals to permit the additional railway car to be added or removed from the train.
More recently, electrical connectors have been incorporated into automatic railway car couplers. The automatic couplers permit coupling or uncoupling of railway cars from a railroad train without manual intervention, and the automatic couplers can be equipped with electrical connectors which automatically make contact with the control circuits in adjacent cars without requiring manual connection or disconnection of the electrical connectors between adjacent cars. For example, a coupler for use on light rail vehicles is manufactured by Dellner-Schaku, Inc. of Mount Prospect, Ill. Couplers of the appropriate type are sold under their model numbers Type 31 and Type 32. The couplers have side-mounted retractable electrical heads which will connect up to seventy-five electrical signals. Another coupler sold by Dellner-Schaku is sold under its Type 26 designation and is a fully automatic coupler designed for rapid transit vehicles and other rail vehicles as well. The coupler is said to be self-aligning, both horizontally and vertically and contains electrical contacts in the form of two side-mounted retractable electrical heads. Uncoupling of the coupler can be accomplished either automatically from the driver's console or manually on the coupler.
While such automatic railway car couplers having self-connecting electrical couplers are advantageous for eliminating the requirement to have a railroad employee effect a manual connection or disconnection of the electrical connections, the contacts in such automatic couplers are subject to environmental contamination and damage. Thus, the quality of the contact between control circuits in adjacent cars becomes difficult to control, and requires frequent inspection of the electrical contacts in the connectors to ensure that a reliable electrical connection is made between control circuits of adjacent cars. This detriment become particularly important in railway applications where the number of railway cars used to make up a train changes frequently depending on passenger load conditions. For example, it is desirable to have railway trains of sufficient length (that is composed of a sufficient number of railway cars) in the morning and afternoon to accommodate rush hour traffic, but to remove excessive numbers of cars during midday and evening operations so that the size of the train matches the expected passenger load. Obviously, the act of making up or breaking down railway trains to accommodate the anticipated passenger load requires the connection or disconnection of electrical connectors between adjacent cars each time that a car is added to or removed from a train. Needless to say, mechanical action associated with frequently connecting or disconnecting adjacent electrical connectors can adversely affect the electrical performance of the contact in the connector and can lead to contamination of the contacts when the connectors are disconnected and are subject to ambient environmental conditions.
Use of fiber optic bundles to transmit signals between adjacent railway cars would be advantageous in that many signals could be multiplexed on a fiber optic carrier and the resulting optical signal could be transmitted between adjacent cars. Fiber optic connectors are known in the art which would permit the connection and disconnection of optical fibers, however, such connectors expose the ends of the optical fiber to environmental contamination when the connectors are disconnected. The ends of the optical fibers may be protected by manually sealing the ends with an end cap or other means, however, this expedient requires manually placing a cap on the end of the fiber optic connector each time that it is disconnected from its adjacent connector. Obviously, this arrangement would be difficult to implement for railway cars which may be frequently connected or disconnected from adjacent cars to make up a railway train. Furthermore, cleaning the end of a fiber optic bundle to ensure the complete removal of environmental contamination requires skilled personnel who would typically not be available to perform this service on a routine basis. Thus, while the use of fiber optics to transmit control signals between adjacent railway cars is advantageous, a means for automatically connecting and disconnecting adjacent fiber optic bundles on adjoining cars would be desirable. Furthermore, it would also be desirable if such means for connecting and disconnecting adjacent fiber optic bundles included means for protecting the ends of the fiber optic bundles from environmental contamination.
Accordingly, a need exists for a means of connecting control signals between adjacent cars in a railway train which avoids environmental contamination affecting the quality of the signal transmitted between adjacent railway cars. A further need exists for a connector in which coupling and uncoupling can be accomplished automatically without manual intervention.